Series-operated studio arc lamps



Feb. 8, 1 927. 1,617,314

T. HALL SERIES OPERATED STUDIO ARC LAMPS Filed May 20. 1920 INVENTOR 7z700/? HALL A1". QRNEY Patented Feb. 8, 1927.

UNITED STATES PATENT OFFICE.

THEODORE HALL, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE SPERRY GYROSGOPECOMPANY, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

SERIES-OPERATED STUDIO ARC LAMPS.

Application filed May 20,

This invention relates to are lamps, and more specifically toautomatically controlled arc lamps adapted to be connected to operate inseries for bank lighting. In my copending application, Serial No. 377,743, filed April 30, 1920, for projector lamps, I described in detailan automatically controlled arc lamp adapted for use in motion pictureprojection. An object of the present inven- 1 tion is to devise a methodof operating such or similar lamps in series for use in motion pictureproducing studies, or for other purposes. An important advantage of soconnecting the lamps is that where several lamps are required and thevoltage available is in excess of a multiple of the value required tooperate one of the lamps, as for instance, where the voltage availableis 110 and each lamp requires 50 v., by connecting two lamps in series,a rheostat capable of effecting a drop of 10 v. at the normal currentemployed will sufiice to care for both lamps, whereas otherwise aseparate rheostat capable of effecting a drop of 60 v. is

required for each lamp.

The principal object of the invention, is to devise a method ofoperating the lamps whereby an enormous saving in energy which wouldotherwise be dissipated in heat is'etfected.

A further object is to greatly reduce the weight and bulk of the lampunits by this reduction in the amount of resistance necessary.

Referring to the drawings wherein I have shown what I now consider to bethe preferred form of my invention:

Fig. 1 is a side elevation of an automatically controlled arc lamp.

Fig. 2 is a wiring diagram showing a plurality of lamps arranged inaccordance with my invention. Q

In Fig. 1 the lamp is shown as comprising two portions 1 and 2 securedtogether as b 5 means of screws 3, but insulated from eac other by meansof insulation 4. The portion 1 is shown as supporting a carriage 5slidably mounted-on a guide rod 6 and having threaded engagement at 7with a rotatable rod 8. Guide rod .6 is preferably also rotatable and isprovided with a keyway 9. A gear 10 slidably mounted on rod 6 may have aprojection, not shown, engaging in keyway 9. The said gear meshes with agear 11 1920. Serial No. 382,817.

fixed on an electrode holder 12 rotatably carried by carriage 5. Thepositive electrode 13 may be gripped by said holder adjacent its rearend, and may project through a guide 14 near its burning end 15. Fixedon rods 6 and 8 are ratchets 16, 17 adapted to be actuated by pawls 18,19 secured to a carriage 20 which is in turn connected by a link 21 to amotor 22 for reciprocation up and down.

Preferably motor 22 runs continuously during the operation of the lamp.and pawl 18 is in constant engagement with ratchet 16, so that rotationof rod 6, gear 10, and gear 11 will efiect continuous rotation ofelectrode 13. Pawl 19, however, is preferably normally disengaged fromratchet 17, so that it normally reclprocates without actuating ratchet17. Energization of a magnet 23 is adapted to throw pawl 19 intoengagement with ratchet '17. This will effect rotation of rod 8 toadvance the carriage 5 and electrode 13. Energization of magnet 23 iseffected through the third electrode 39 in response to the position ofthe end 15 of electrode 13.

Portion 2 of the lamp may be provided with a carriage 24 slidablymounted on a guide rod 25 and in threaded engagement with rod 28. Therear end of the negative electrode 26 may be gripped by said carriage24.- while the forward end protrudes through a guide 27. Rod 28 may beprovided with an elongated pinion 29 meshing with a gear 30 on the sameshaft 31 as bevel gear 32 which in turn meshes with bevel gear 33 onshaft 34. The said shaft is divided and insulated at 35 so as not to actas a short circuit between the two portions of the lamp. The oppositeend of this shaft is provided with a ratchet 36 adapted to be actuatedby pawls 37 fixed on the rec1pr0- catory carriage 20. The said pawls arenormally disengaged from ratchet 36, but are brought into engagementtherewith by a yariation up or down of the current passlng throughelectromagnet 38 so as to rotate rods 34 and 28 to move electrode 26toward or away from electrode 13.

The apparatus thus far descrlbed is disclosed in great detail in myaforesaid copending application.

In order to effect a rapid striking of the arc I have shown rod 28 ashaving long hearing portions ermitting longitudinal sliding ofsaid rod trough its bearings 41, while the lower end 42 of the rod constitutes thecore of a solenoid 43 fixed to the lamp. A spring 44 engaging a stop 45at one end and at the other a plate 46 against which the end of the core42 bears rotatably, normally presses rod 28 upwardly and this in turnmaintains electrode 26 in contact with electrode 13. Solenoid 43 may bein series with the are so as to be energized throughout the period thatthe current is flowing. As soon as the current is turned on and flowsfrom one electrode to the other by reason of their physical contact, thecore 42 will be attracted y solenoid 43 to draw rod 28, carriage 24, andelectrode 26 downwardly to the position shown, thus striking the arc.

As shown in the Wiring diagram in Flg. 2, several of such lampsA, B, andC-may be connected in series for operation. he

current entering through supply line 45.

flows through coils 38,43, electrode 13, across the arc 46, throughelectrode 26 of lamp A, conductor 48, and through the similar elementsof the other lamps B and O successively and back through line 49.

As stated, the positive and negative electrodes of the lamps arenormally in contact so that a complete circuit through the electrodes isestablished as soon as the current is turned on and energization of allof the solenoids 43 is efiected and the are im- 'med'iately drawn in allof the lamps. The

the lengths of the several arcs 46.

' motor 22 for continuously actuating the rethe other in response to theresistance in the circuit will thus adjust the length of arc in lam A soas to maintaina constant amperage 1n the entire circuit and consequentlyacross all of the arcs. The magnets 38 controlling the feeding of thenegative electrode of lamps B and C are, on the other hand, connected inshunt with their respective lamps. Thus the strength of these magnetswill becontrolled in accordance with the length of arc in theirrespective lamps, andbeing adjusted. to a redetermined neu tral point,will control t e feeding of their negative electrodes toward or awayfrom the positive whenever the arc len h tends to vary. In this way,coil 38 of amp A will 1113111173111 constant amperage across all of thearcs and an arc length in lamp A in accordance with the voltage in thesupply lines 45, 49.

To regulate the arc length in lamp A then I may provide means for reulating the *voltage of the. lamp circuit. 0 viously such means may beeither manually or automatically operated. The means here showncomprises a rheostat 50 interposed in the supply line. The arm 51 ofthis rheos'tat may be connected to a gear 52 for actuation. A pinion 53meshing with said gear may be provided on the shaft 54 of a motor 55.The field 56 of said motor may be connected across the supply lines asshown, while the 1 armature 57 thereof may be connected throughconductors 58, 59 to the blades 60, 61 of a reversin switch 62. Theswitch is shown in neutral position so that no current will be suppliedto the armature 57. The rear arm 63 of the switch may constitute thearmature of an electromagnet 64 shunted across the supply lines 45, 49between the rheostat and the lamps. An adjustable tension spring 65 maybe provided to oppose the action of magnet 64'upon armature 63. Turningof screw 66 in fixed member 67 will regulate the tension of spring 65 soas to hold the switch inthe centralized position shown when the voltageis of a predetermined value. An increase or decrease in the voltagewill. result in the turning of the switch onits axis 68 to throw switchblades 60, 61 into engagement'with contacts 69, 70 on the one hand, or71, 72 onthe other. Thus on the one hand current will flow from thepositive side through conductor 73, contact 69, switch blade 60,conductor 58, armature 57, conductor 59, switch. blade 61, contact 70,conductor 74 to the negative side and the motor will turn in onedirection to actuate arm 51 of rheostat 50 to throw in more resistance,while on the other hand the current would flow through conductor 73,contact 72, blade 61, conductor 59, arma ture 57, conductor-58, blade60, contact 71, and conductor 74 to the negative side to turn the motorin the opposite direction to decrease the resistance. In this way thevoltage supplied to the lamps may be maintained substantially constantand this. in turn will maintain a substantially constant arc length inlamp A.

The third electrode 39 is shown as connected' through conductor 75 andelectromagnet 23 to line 48, so that as the crate: end 15 of thepositive electrode tends to recede by reason of consumption, the flame76 will touch said third electrode, completing a circuit throughelectrode 13. The magnet 23 will thus be connected to shunt with the arcand will effect the feeding of the positive electrode as pointed out. i

It should be noted that while I have shown three lamps to illustrate myinvention, it'is obvious that two lamps instead of three may he used;the lamp C being omitted and conductor 48 of lamp B being connecteddirectly to supply line 49. On the other hand, it is equally obviousthat several additional lamps may be added to the series. It should alsobe noted that although separate striking solenoids 43 are shown for thelamps the. lamps would operate successfully without such solenoids asshown in my prior application 377,743. Of course in such event no one ofthe lamps would draw an arc until all drew the arc. This would cause nodifiiculty provided the lamp having the shunt coil 38 should strikebefore the lamp having the series coil 38. Such action may of course, beinsured by making the normal .rate of feed of the first mentioned lamp.

somewhat faster than the rate of feed second mentioned lamp.

In accordance with the provisions of the patent'statutes, I have hereindescribed the principle of operation of my invention, to-

of the gether with the apparatus, which I now. consider to represent thebest embodiment thereof, but I desire to have it understood that theapparatus shown is only illustrative and that the invention can becarried out by other means. Also, while it is designed to use thevarious features and elements in the com bination and relationsdescribed, some of these may be altered and others omitted withoutinterfering with the more general resultsoutlined, and the inventionextends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent lsz 1. In combination, a plurality of seriesconnected arclamps, means for automatically regulating the voltage supplied to saidlamps, means controlled by a coil shunted across each lamp for effectingthe feeding of one of the electrodes thereof, means controlled by a coilin series with said lamps for effecting the feeding of the other of theelec trodes of one of the lamps, means controlled by separate coilsshunted across each of the other of the lamps for eflecting the feedingof the other of the electrodes of said other lamps, and means wherebysaid secondnamed means are controlled by the position.

of the arc flame.

2. In combination, a plurality of serieslating means for controlling thearc length of said one of the lamps.

4. In combination, a plurality of seriesconnected arc lamps, meansresponsive to the position of one of the electrodes in each lamp foreffecting the feeding of such electrodes, electromagnetic meanscontrolled by the current in all of the lamps adapted to control the arclength'in one of the lamps, electromagnetic means in shunt with theothers of said lamps for controlIin the arc lengths thereof, and meansfor maintaining constant the voltage in said lamps.

5. In combination, a plurality of arc lamps connected in series, meanswhereby variations in the amperage of the circuit are taken up by one ofthe lamps to maintain constant the amperage in all of the lamps, andmeans for maintaining constant the arc length of said one lamp.

6. In combination, a plurality of arc lamps connected in series, voltagecontrolled means for feeding an electrode in one of said lamps, meansfor feeding an electrode in another of said lamps and a voltageregulator and a current cont-rolled element for controlling said secondmentioned feeding means.

7. In combination, a plurality of arc lamps connected in series, acurrent responsive coil in series with the are on one of said lamps,means controlled thereby for effecting the feed of said lamp and therebyregulating the current supplied to all of said lamps, a voltage coil oneach of the other of said lamps, and means controlled thereby foreffecting the feeding thereof in accordance with the arc length.

In testimony whereof I have aflixed my signature.

THEODORE HALL.

